<!DOCTYPE html>
<style>
    .d1 {
        position: absolute;
        left: 10.5px;
        width: 100px;
        height: 100px;
        background-color: red;
        border: 1px solid green;
    }
    .d2 {
        background-color: green;
        width: 100%;
        height: 100%;
    }
</style>
<div class="d1"><div class="d2"></div></div>
<script>
    function finishTest() {
        setTimeout(function() { testRunner.notifyDone() }, 0);
    }
    if (window.testRunner) {
        testRunner.waitUntilDone();
        testRunner.setBackingScaleFactor(2, finishTest);
    }
</script>
